Propeller



W. SCO

PROPELLER Filed May 27, 19

4 Sheets-Sheet 1 w n m HM MN Qw Q w E J 1 I E. Q g, N, M, 3 1 I I r 1, ln w W h mm wk A IIR. x Q Q L I 8 N\ F N NM 3 3 mm w m t E & d W T NINVENTOR ORI N W. SCOTT $3M, ATTORNE Y nitd S9165 3,029,876 PROPELLERGrin W. Scott, Wichita, Kans., assignor to Beech Aircraft Corporation,Wichita, Kans., a corporation of Delaware Filed May 27, 1960, Ser. No.32,322 4 Claims. (Cl. 170-16058) The invention here disclosed relates topropellers, particularly of the constant speed type.

Objects of the invention are to provide improved retention means for thepropeller blades which will eliminate need for the customary split hubor machined hub thread constructions and which will be of particularlysimple and inexpensive design.

Other special objects of the invention are to provide a propeller hubstructure which may be arranged for either pressure operation to highpitch or the reverse and which may be arranged to be either singleacting or as a full feathering propeller.

The foregoing and other desirable objects are accomplished by certainnovel features of construction, combinations and relation of parts, allas hereinafter set forth, illustrated in the accompanying drawings andbroadly covered in the claims.

The drawings accompanying and forming part of this specificationillustrate a present practical embodiment of the invention. Structurehowever may be modified and changed as regards the immediateillustration, all within the true intent and broad scope of theinvention as hereinafter defined and claimed.

FIG. 1 in the drawings is a substantially central longitudinal sectionalview of a propeller having the invention incorporated therein withportions broken away and with the blade at the top shown rotatably heldin its socket and the blade at the bottom lifted for entry of thebearing balls which lock the blade in place.

FIG. 2 is a transverse broken sectional view of the same onsubstantially the plane of line 22 of FIG. 1.

FIG. 3 is a broken horizontal sectional view on substantially the planeof line 33 of FIG. 2.

FIG. 4 is a broken sectional view illustrating a modified form of meansfor holding the blades locked in place.

FIG. 5 is a broken sectional view similar to FIG. 2 showing a one-pieceouter race ring substituted for the split ring first illustrated.

FIG. 6 is a cross sectional view on substantially the plane of line 6-6of FIG. 5 showing the hub socket notched for entry of the one-piece ringand this ring with flats on opposite sides to facilitate entry into thehub.

In the embodiment of the invention illustrated in FIGS. 1, 2 and 3 threis a one-piece aluminum hub body 5 having cylindrical sockets 6 for theblades 7 and these blades have cylindrical shank portions 8 which willfreely enter and then be caught and be rotatably held in the sockets.

The retainers for the blades are the bearing balls 9 operating betweenthe outer split race ring 10 seated on shoulders 11 about the sockets 6and the inner split race rings 12 seated on shoulders 13 on the innerends of the cylindrical shank portions 8. The inner race ring asindicated in FIGS. 1 and 2 is enough smaller than the outer race ring topermit insertion of the blades with the inner rings in place, throughthe outer race rings.

Access for the bearing balls between the races is provided by displacingthe blade shanks inwardly, as indicated at the bottom in FIG. 1, toseparate the raceway rings far enough for the balls to enter wheninserted through the open front of the hub at 14, before completeassembly.

After all the balls for one bearing have been dropped into place theblade is shifted outward to its normal position with the balls properlyengaged between the opposing rings as shown at the top in FIG. 1.

After loading the bearings in this way and thus locking the blades inplace the parts are secured in this relation by inserting spacers 15between the flanges 16 on the blades and supporting washers 17 of nylonor the like Which washers may be seated in depressions 18 about theouter ends of the blade sockets.

These locking spacers are shown secured in place by screws 19 extendedthrough the blade flanges 16.

These ball bearing retainers assembled in this way permit a one-pieceform of hub body and eliminate any need for machiningscrew threads inthe hub structure as in conventional practice.

The split outer race rings 10 will normally hold in place in their seatsin the hub of themselves and the split rings on the blade shanks may besecured on the shanks by encircling retainer wires 20 received ingrooves 21 in the companion ring parts, or the equivalent.

The construction disclosed is compact and takes up small space, leavingample room in the hub for the hyv draulic shift mechanism shown in theform of piston 22 operating in stationary cylinder 23 on the front ofthe hub and carried by a tubular piston rod 24 open to hydraulicpressure from the tubular propeller shaft 25 and carrying a yoke 26having outstanding arms 27 connected by pivot links 28 with pins 29 onarms 30 connected with the respective blades.

The forward side of the piston .is shown in FIG. 1 as abutted with a lowpitch stop plug 31 adjustably screwed at 32 in an extension 33 of thecylinder and secured in adjusted relation by a lock nut 34.

The inner end of the stop plug is shown hollowed at 35 and ported in theside at 36 to pass fluid from the tubular piston rod by way of a centralport 37 in the head of the piston.

The pitch change mechanism or the inner portions of the same may beinstalled before the blades are seated. FIG. 1 shows, at the bottom, howthis mechanism does not interfere with the inward displacement of theblades required for inserting the balls.

A conventional governor may be used to boost engine oil pressure appliedto the piston, which in this case is connected to force the bladestoward high pitch (low rpm). The reverse action may be accomplished byapplying the oil pressure to the opposite side of the piston andcounterweighting the blades in rotary toward high pitch. Also it will beappreciated that while a single acting propeller is shown the inventionmay be applied to a feathering propeller and or feathering and reversingpropellers.

In addition to reduced manufacturing and assemblage costs the propellershown has advantages in the simplicity of blade retention and lowerweight than in the usual split hub constructions or structures requiringthe use of hub threads.

Assembling is facilitated and weight is kept down by cutting away theinner wall surface of the hub ends immediately inside the seats 11provided for the inner race rings substantially as indicated at 38 inFIGS. 1 and 2. As particularly shown in FIG. 1 this provides ampleclearance for the bearing balls when the blades are shifted inwardly toopen up space between the opposed bearing rings.

The simple compact, light weight structure afforded by this invention isparticularly desirable for low cost constant speed propellers.

A hearing for supporting and guiding the inner end of the hollow pistonrod is shown at 39, FIG. 1

A high pitch stop may be provided, such as an annu- Patented Apr. 17,1962 lar shoulder 40 on the front of the hub, engageable by the innerside of the piston.

With the construction disclosed no special opening is required for entryof the bearing balls. The balls are simply dropped in through theopening in the front of the hub, then the blade is pulled out to correctposition and spacers 15 installed to keep the blade in this relation.

Removal of the blade is the reverse, spacers 15 being taken out afterremoving the screws 19. The blade then is moved further into the hub andin this position the balls will drop out from between the races.

An alternate method of holding the blades in final position is shown inFIG. 4. This consists in providing a screw thread 41 on the blade and aring nut 42 engaged with the thread to bear against a washer 43 seatedon the hub. This is a simpler construction than that with the splitspacers. The screw thread does not require special development since itis on a large portion of the blade shank, having low stresses and theonly load carried in the thread is that of the weight of the blade instatic position and loading that may result from engine backfire, whichis low.

Under some circumstances a one-piece ring for the outer race, instead ofthe spit ring construction first disclosed may be preferred.

This variation is illustrated in FIGS. and 6 where the outer race ring10a is a continuous one-piece member which can be entered edgewisethrough opposed slots 44 cut in the end of the blade socket and then beturned into position seated against the shoulder 11.

To keep the notches 44 as small as possible and to facilitate thisassembly operation the race ring may be made with clearance flats 45 onopposite sides.

What is claimed is:

1. A propeller comprising a hub having cylindrical blade sockets andinternal undercut annular shoulders about said sockets, outer race ringsseated on said internal shoulders, said outer race rings having inwardlyfaced ball tracks, the hub being enlarged inwardly of said outer racerings in the form of annular cavities open to said outer race rings,blades having cylindrical shanks insertable in said sockets through saidouter race rings into position opposite said annular cavities, saidshanks having external annular shoulders on the inner ends of the same,inner race rings seated on said external annular shoulders, said innerrace rings being of a size to pass through said outer race rings and theblade shanks having movement inwardly in the sockets suflicient to carrythe inner race rings clear of the outer race rings far enough for entryof bearing balls between companion race rings, the inner race ringshaving outwardly faced ball tracks opposed to said annular cavities whenthe blade shanks are fully entered into the sockets, the hub having anentry for admitting bearing balls into said annular cavities about theentered blade shanks, bearing balls of a size to match the companionrace rings in the running position of the blade shanks in the sockets,said annular cavities being enough larger in diameter than the insertedblade shanks to freely receive said bearing balls whereby to hold a rowof balls about the fully inserted end of a blade shank so that saidballs may pass from that annular cavity into position between thecompanion race rings and whereupon said blade shank may then be shiftedoutwardly in its socket to lock the row of balls between the race ringsand whereupon such blade will then be rotatably held against furtheroutward movement in its socket and releasable means for rotatablyretaining the blades in said outwardly shifted position with the enteredrows of bearing balls holding the blades in their sockets.

2. The invention according to claim 1 in which said means for retainingthe blades in outwardly shifted relation comprises flanges on the bladesexternal of the hub, spacers removably inserted between said flanges andthe hub and means removably securing said spacers in relativelyrotatable relation between the blade flanges and hub.

3. The invention according to claim 1 in which said outer race rings areof one-piece construction and the hub having opposed notches in the endsof the sockets for admitting said one-piece rings in on-edge relation.

4. The invention according to claim 3 in which said one-piece rings haveflats on opposite edge portions of the same to facilitate entry of therings through said notches.

References Cited in the file of this patent UNITED STATES PATENTS2,107,785 Grabararse Feb. 8, 1938 2,425,261 Murphy et al Aug. 5, 19472,438,542 Cushrnan Mar. 30, 1948 2,523,053 Obrist Sept. 19, 19502,533,415 Anderson Dec. 12, 1950 2,612,961 Kapsenberg Oct. 7, 19522,623,601 Frankland Dec. 30, 1952 2,718,268 Cushrnan Sept. 20, 19552,807,327 Scott Sept. 24, 1957 2,913,057 Willi Nov. 17, 1959 FOREIGNPATENTS 494,812 Great Britain Nov. 1, 1938

